Display Message On MouseOver In an ASP.NET GridView

To display a message in an ASP.NET GridView on MouseOver, handle the RowDataBound event. As given in MSDN,

The RowDataBound event is raised when a data row (represented by a GridViewRow object) is bound to data in the GridView control. This enables you to provide an event-handling method that performs a custom routine, such as modifying the values of the data bound to the row, whenever this event occurs.